The present invention relates to a pole change dynamo-electric machine with a three-phase stator winding adapted for reconnection to form either one of two pole numbers having a ratio of 1:2 and adapted for reconnection for operation on either one of two voltages having a ratio of about 1:2.
Pole change dynamo-electric machines, such as three-phase induction motors, adapted to have either one of two pole numbers having a ratio of 1:2, e.g., either two poles or four poles, have been known which are operable on a single voltage. Where it is required that such a pole change dynamo-electric machine is operable on either one of two different voltages having a ratio of, for instance, about 1:2, pole change dynamo-electric machines with separate windings for different pole numbers have been used. Pole change dynamo-electric machines with separate windings have a large stator core and are hence bulky, and require a large amount of copper and making them costly. Moreover, voltages are induced in the winding which are not used, and circulating currents may flow through the winding, depending on the manner of connection of the winding, and may cause burning of the winding.